We (probably) haven't invented a fully functional sonic screwdriver just yet. But scientists are hard at work using sound waves to manipulate items in the laboratory. Last summer a Swiss research team managed to lift multiple objects with acoustic levitation—strategically placed sound waves. And sonic medicine is far from fiction. Physicians have relied on sound-pressure waves for medical imaging since the 1940s (think ultrasounds), and recent research suggests that high-frequency ultrasound therapy, or HIFU, could treat some cancers.

K9

K9

The robotic dog that inspired its own spin-off series, K9 is the Fourth Doctor's lovable, automated pet. After a few system reboots, the mechanical mutt could follow commands, fly through space, and beat the Doctor at chess in only six moves.

Earth scientists probably have the technology to develop a flying, chess-playing robot. The U.S. Navy tested a fully automated airplane last year. Robots have been embarrassing human chess champions for years. And while no one could build a RoboDog as cute as K9, NSK Ltd, a Japanese company, certainly tried. In 2011 NSK developed a four-legged mechanical guide dog that used sensors to interact with its environment and negotiate staircases. Unfortunately, the final prototype released in 2013 lacks much of the charm of the original robot pup.